Question about Data Usage

When I check the Cellular Network Data in the Usage section of my iPhone, it gives me 2 figures, one for data sent and one for data received. I am just wondering if this relates to my monthly data plan, which is 1gb. If so, is it the sum of these two numbers that determines how much data I have used off my plan? Thanks.

P.S. On an unrelated note, if I download an app that plays radio stations, does that use the actual radio signal or does it stream it off the internet?

Monthly data usage on your cell plan is in fact as you thought your upload and download combined. However like your home connection your upload is only a fraction of the speed of your download especially on a mobile device so it will only make up a very small amount of your monthly data usage.